On 29 May 1944 U-549 slipped undetected through the screen of the hunter-killer group TG 21.11, formed around USS Block Island (CVE 21) (Capt F.M. Hughes, USN) and at 20.13 hours fired three T-3 torpedoes at the carrier about 300 miles west-northwest of the Canary Islands. Two of them struck the ship, followed by another torpedo as coup de grâce about eight minutes later that caused the carrier to sink at 21.55 hours.

At 20.40 hours USS Barr (DE 576) (LtCdr Henry Hamilton Love, USNR) was damaged by a Gnat in the stern and a second Gnat missed USS Eugene E. Elmore (DE 686). But the U-boat was then attacked and sunk by the latter destroyer escort and USS Ahrens (DE 575).

USS Barr (DE 576) was on her first war voyage and the torpedo explosion completely wrecked the ship aft of #2 engine room, killing 15 crew members and injuring 14 others. Two of them died of wounds the next day and were buried at sea. The following morning the injured and about half of her crew were transferred to USS Eugene E. Elmore (DE 686), which took the badly damaged destroyer escort in tow, screened by USS Robert I. Paine (DE 578). The destroyer escorts were later relieved by USS Wilhoite (DE 397) and the Dutch tug Antic took over the tow, arriving in Casablanca on 5 June. After temporary repairs USS Barr (DE 576) was towed by USS Cherokee (ATF 66) to Boston, arriving there on 25 July.

The vessel was converted to an auxiliary high speed transport of the Crosley class, reclassified (APD 39) and re-entered service in November 1944.

More information about the engagement between the hunter-killer Task Group 21.11 and U-549, including photos of the damaged destroyer escort can be found in the U-boat Archive: U-549 sunk by USS Eugene E. Elmore and USS Ahrens on 29 May 1944